Chemical Bonding: The combining of atoms of elements to form new substances.

Valence Electrons: The electrons in the outermost energy level.

Chemical bonding depends on the valence electrons (because these are the electrons that can interact w/ other atoms).

energy levels (where electrons live): First Energy- can hold up to 2 electrons Second - Can hold up to eight.

Atoms are happy (they do not react) when their outer energy level is full. ex. The Noble Gases are inert (don’t react w/ anything) because their outer shell is full.

For Web example: Barium has 2 electrons in its outer shell Flourine has 7 (THEY BOTH WANT 8) Now Go ToBond Animation and see what happens!

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Notes cont...

The above was a demonstration of an ionic bond forming. Ionic bonds are bonds that involve the transfering of electrons. (Stealing of electrons)

Positive ions form when electrons are lost... Na tends to lose 1 electron. So it has a +1 charge. Negative ions form when electrons are gained... Cl tends to take 1 electron. So it has a -1 charge.

After the transfering is done, the charges do the work. Opposites attract. The only goal is that the total charge is zero. Na+1 Cl-1 ... NaCl Al+3 O-2 ... Al2O3

Ionization: The process of removing electrons to form an ion. (This process takes energy) Ionization Energy: Low for atoms w/ few valence electrons (they are more than happy to lose them) and high for those w/ almost a complete shell (they would rather gain a couple).

Electron Affinity: The tendency for atoms to attract electrons. Fluorine has a high electron affinity...Why?...What other elements have a high electron affinity?

One last thing about ionic compounds...They like to form crystal lattice structures. They fit together like puzzle pieces in a regular repeating pattern.

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Covalent compounds (MOLECULES)

DO NOT FORM IONS!!! Covalent bonds arise from a sharing of electrons. The nucleus(+) of each atom attracts the electrons(-).

LEWIS DOT STRUCTURES: electron dot diagram. (See the link below any more questions, ask me or the book page 183-182)

Metallic Bonds

A network of positively charged metal nuclei and free roaming electrons (a common electron cloud). What properties of metals does this help to explain?

*********************************************** * Special Note: The column (excluding transitions) tells you how many valence electrons. The row tells you how many energy levels.

Draw dots around the symbols, single first then double. Connect single dot s to single dots of other (oppositely charged) element. Do this till all single dots are gone! * *************************************************